Snap fastener



United States Patent Office lhhh@ Patented July 20, 19654 3,195,26@ SNAP FASTENER Dornenc J. Daddona, Jr., Waterbury, Conn., assigner to Scoviil Manufacturing Company, Waterbury, Conn., a corporation of Connecticut Fitted Feb. 9, 1962, Ser. No. 172,221 Z Claims. (Cl. 2st- 20%) My invention relates to snap fasteners and particularly to inexpensive fastener elements which can be readily applied to paper and other tearable material. The invention is an improvement in that class of snap fasteners where the stud and socket elements each consists of one thin metal piece with the tubular fastener portion, either the socket or stud, arranged centrally and providing a relatively wide base adapted for attachment to the fiat surface of the article to be fastened. Such fasteners are useful especially for envelopes where one element is secured to the flap and the other to the body of the envelope.

An object of the invention is to provide an improved fastener element construction with a maximum number of attaching prongs so as to obtain an intimate bonding of the flat metal base to the paper surface of the envelope.

Another object is the provision of a particular arrangement of the attaching prongs so that they are adapted for economical attachment to the envelope by a single operation of a simple punch and die.

My improved arrangement of the attaching prongs also avoids the radially outward projection of the points of the prongs which in prior construction is objectionable since tearing is more easily started by pressure applied inline with the points. My improved arrangement is such that the initial tearing stress comes against the side edge of the prongs rather than the points.

My invention is adapted to an arrangement of the attaching prongs to extend from either side of the base relative to the central fastening element. One of the advantages of having such prongs extend in the direction opposite from the fastening element is that the tubular fastener part does not have to extend through a hole in the paper. In such an arrangement, my invention provides superior strength against tearing because of the novel arrangement of the attaching prongs.

Other objects and advantages of the invention will hereinafter more fully appear.

In the accompanying drawing, I have shown for purpose of illustration one embodiment which the invention may assume in practice. In the drawing:

FIG. 1 is a plan view of a snap fastener socket element embodying my invention;

FIG. 2 is a central vertical sectional View on line 2-2 of FIG. 1;

FIG. 3 is a plan view of a stud element with one portion showing the prongbending tool in horizontal section, and another portion showing how the attaching prongs are clinched to hold the fastener element in place;

FIG. 4 is a central vertical section on line 4 4 of FIG. 3 and showing the attaching prongs before the clinching operation;

FIG. 5 is a central vertical section through both fastener elements after attachment to an article such as a paper envelope;

FIG. 6 is a perspective view showing the end of the prong clinching punch;

FIG. 7 is a perspective view of the end of a supporting die used in clinching the prongs;

FIG. 8 is a vertical central section showing the position of the clinching tools where the fastener attachment is complete; and,

FIG. 9 is similar to FIG. 8 but showing the tools at the beginning of the prong bending action.

The socket fastener element seen in FIGS. 1 and 2 consists of a single piece of thin metal having a relatively wide and preferably circular base 10 with a tubular socket located centrally thereof and consisting of a series of spring lingers 11 with inturned ends 12. The means for attaching the fasteners to a supporting sheet such as indicated by 13 in FIG. 5, consists of the desired number of prong clusters arranged centrally of the base, or concentrically of the tubular fastening means. Each of these prong clusters is formed by a nail-like punch with its end shaped like a four-sided pyramid. When such punch is forced through the thin base material, it cuts and draws up four prongs 14, 15, 16 and 17 in each cluster. The prongs 14 and 15 may be referred to as one pair while 16 and 17 are another pair. It will be observed that the two prongs of each such pair of all clusters are arranged on opposite sides of a circle 18 extending midway between the prongs of each pair, and that this circle 13 is concentric with the tubular fastener means and with the base 10.

This arrangement lends itself to easy attachmentof the fastener elements by simple tools like the punch 19 and die 2G. The die has a circular recess 21 of a depth suilicient to receive the circular base 10, and the punch has a circular dome-shaped ridge 22 aligned with the circle 1S. As the punch 19 engages the prongs in the manner shown in the upper portion of FIG. 3 and in FIG. 9, the dome-shaped ridge 22 will strike the inner edges of the outer prongs 14 and 17 and the outer edges of the inner prongs 15 and 16 so that they will all bend outwardly of the hole 23 between the prongs of each cluster, and nally be clinched over as seen in FIG. 8 against the material of the article 13.

While the attaching prongs are sharp and will pierce their way readily through the material 13, it is necessary to form a hole through which the fingers 11 of the socket element may extend. As the setting punch 19 descends, a central spring-loaded sizing punch 24 will enter the opening in the tubular socket and punch out a disc 25, shearing against the inturned ends 12 of the socket lingers 11. Downward travel of the sizing punch 24 is now stopped, and as the setting punch 19 continues down, the outside diameter of the socket element will enter the base 24a and shear out a doughnut-shaped blank 25a thereby providing an opening through which the socket head may project. As initially formed, the prongs are made to flare outwardly to some extent from the center of each cluster so that they will always bend in the proper manner when engaged by the punch 19.

The stud element of the snap fastener is of substantially the same construction having a circular base, also designated 1t?, and a hollow tubular stud element 26 adapted for snap fastener engagement with the socket fingers 12. However, in this instance, the prongs, all of which are designated 27, extend from the base 10 in a direction opposite to the fastening means 26. In this case, as seen in FIG. 5, there is no necessity for a hole in the material 28 and of course, the attaching prongs of the socket element could likewise be made to extend in the direction opposite of the socket with a like advantage.

It will be seen at the lower portion of FIG. 3 that the attaching prongs are all of triangular shape, and when clinched over against the material, the points of the outer prongs do not project in a direction radially of the fastener base, but rather the edges 29 extend in a direction generally normal to a radial line passing through the center of the base 10 and the center of hole 23 between the prongs of each cluster. The result here is that when a pull is exerted on the material around the fastener, such as required to unsnap the fastener, the stress will come against the broad edges 29 rather than on the points so that there is much greater resistance to tearing, especially when the prongs extend through the material on the side of the base from the central fastening means. Y

The inner series of prongs, which are numbered 15 and 16 forthe socket element, aid in securing the fastener element base in intimate'contact with the face of the supporting material.

While I have shown for purposes of illustration only four prong clusters, it may be desirable to provide in some instances, at least six such clusters so as to provide the maximum strength.

When the attaching prongs are struck out and drawn up from the thin metal base, there may be left between the prongs some slightly ragged edges as indicated at 3G. The prongs are all longer than the radius of the hole 23 from which they are drawn and this is accomplished by stretching or thinning the material by the sides of the naillike punch and complemental die. The prongs are not only elongated but thinner than the original base metal,

Vand if desired, the points can bermade quite sharp for easy penetration of the material during the attaching operation.

What I claim is:

1. A one-piece thin metal snap fastener element com- Y prising a generally atbase, fastening means located centrally of said base adapted for snap engagement with of flexible supporting material comprising a plurality Vof prong clusters spaced equidistantly from the center of said base, each cluster consisting of two pairs of prongs, the two prongs of each pair in all clusters being situated wholly on opposite sidesof a circle vpassing centrally of the clusters midway between the prongs of each pair, the lcenterof Vsaid circle being the same as the center of said base.

2. A one-piece thin metal snap fastener element as delined in claim 1 wherein the plurality of prong clusters are struck up from said base, leaving a hole in the base between the prongs of each cluster, the prongs consisting of thinnerV material than the base and each being substantially longer than half the distance across the hole from which it was struck up.

References Cited by the Examiner UNITED STATES PATENTS 798,708 9/05' Simons 24f2l6 Y 2,585,897 2/52 Johnson 24-217 2,996,237 8/ 61 Hines.

' FOREIGN PATENTS 848,941 8/39 France. 'Y

DONLEY I. STOCKING, Primary Examiner. ABRAHAM G. YSTONE, Examiner. 

1. A ONE-PIECE THIN METAL SNAP FASTENER ELEMENT COMPRISING A GENERALLY FLAT BASE, FASTENING MEANS LOCATED CENTRALLY OF SAID BASE ADAPTED FOR SNAP ENGAGEMENT WITH COMPLEMENTARY FASTENING MEANS OF A COMPANION FASTENER ELEMENT, AND MEANS FOR ATTACHING SAID BASE TO THE FACE OF FLEXIBLE SUPPORTING MATERIAL COMPRISING A PLURALITY OF PRONG CLUSTERS SPACED EQUIDISTANTLY FROM THE CENTER OF SAID BASE, EACH CLUSTER CONSISTING OF TWO PAIRS OF PRONGS, THE TWO PRONGS OF EACH PAIR IN ALL CLUSTERS BEING SUITED WHOLLY ON OPPOSITE SIDES OF A CIRCLE PASSING CENTRALLY OF THE CLUSTERS MIDWAY BETWEEN THE PRONGS OF EACH PAIR THE CENTER OF SAID CIRCLE BEING THE SAME AS THE CENTER OF SAID BASE. 